But there’s a big reason Russia and its president, Vladimir Putin, would choose against severely escalating the situation in response: the many economic ties between the two countries.

“Putin’s ability to be pragmatic economically should not be underestimated,” geopolitical expert Ian Bremmer, the president of Eurasia Group, told Business Insider in an email.

“Let’s keep in mind, Russia is still providing gas to Ukraine … and that’s after they invaded,” Bremmer said. “And also, Putin doesn’t want to create more antagonism with NATO just as he’s making progress with the Europeans — France in particular — in turning back the US-led Western ‘isolation’ of the Russians.

“There’s a very significant economic relationship between the two sides — tourism, trade, and most importantly energy — that neither Putin nor Erdogan want to interfere with,” Bremmer added, referring to Turkish President Recep Tayyip Erdoğan.

According to Reuters, Turkey, along with Egypt, is among the largest buyers of Russian wheat, and it is a significant purchaser of Russian semifinished steel products. In 2014, 4% of Turkish exports — mainly textiles and food worth about $6 billion — went to Russia.

Tourism is also heavy between the two countries. In 2014, 3.3 million Russian tourists ventured to Turkey — the second-largest number of tourist arrivals after Germany, Reuters reports.

But the energy relationship between the two is indeed the most consequential for both countries.

Turkey strongly depends on Russia for its natural-gas imports. According to The New York Times, Russia provides more than half of Turkey’s natural gas.

But Russia also depends on Turkey to transport its natural gas into Europe, especially since its ongoing conflict with Ukraine — which lies on another gas-transport route — doesn’t show any signs of slowing.

Both countries are in talks over a natural-gas pipeline project that would enable Russia to transport its natural gas into the EU. When the project was announced in December 2014, while Putin was visiting Ankara, both leaders were presented in the media as uniting together against the West, with whom both have their issues.

Turkey also has a $20 billion deal with a Russian state-owned firm to build a nuclear power plant in the country.

“Putin’s initial reaction — ‘a stab in the back by the terrorists’ accomplices’ — is about as bellicose as could be imagined,” Bremmer said. “But Putin is no stranger to harsh rhetoric, and he has broader interests to play for.”

Relations between Putin and Erdogan have been deteriorating, especially since the start of Russia’s intervention in Syria. Russia has primarily been targeting rebels in Syria unaffiliated with the Islamic State group that are supported by Turkey and other countries.

But common interests between the countries remain, as well as their dependence toward each other.

Erdogan has threatened that Turkey will get its gas from somewhere else and that another country could “come and build” the nuclear plant. And though a different country could indeed come build the plant, getting gas from somewhere else might prove much more difficult.

Russia provides gas to Turkey primarily through two pipelines, one that runs through the northwestern region of Thrace and another through the Black Sea, Reuters reports.

Though Turkey also receives gas from Iran, Azerbaijan, and Turkmenistan, the country could not receive the amount of gas it obtains from Russia through that infrastructure.

Russia is also wary of angering its sole hope at the moment to bring its gas more easily to the EU, especially after the South Stream pipeline through Europe was scrapped.

Said Bremmer: “I don’t think it fundamentally derails the Russia-Turkey relationship, seriously escalates tensions between Russia and NATO, or dramatically changes the dynamics of coalition building around Syria.”